1. Field of the Invention
This invention relates to a reinforcing structure for resisting deflection of a tank wall that is subjected to a range of positive and negative pressures within the tank, and more particularly it pertains to a tank for a transformer.
2. Description of the Prior Art
Power transformers are the subject of constant design changes in order to improve their cost and efficiency. In particular, large tank structures for containing transformers are exposed to varying temperature conditions incurred by internal and external environments. Moreover, transformer tanks are subjected to wide variations in pressure during testing and subsequent start-up periods. For example, when a transformer tank is filled with a dielectric coolant for a liquid-cooled transformer, the tank is preliminarily evacuated to a pressure of about -14.7 psig in order to minimize the gas content of the coolant. During subsequent operation of the transformer the pressure on the tank often reaches a pressure of about 8 psig. As a result a tank wall is subjected to positive and negative pressures within the tank which has created problems in designing transformers having lower cost and higher efficiencies.